Is Neymar coming back? Will there be a Real Madrid revival? La Liga's big questions

Neymar scored 68 goals in 112 appearances during his four-year spell with Barcelona between 2013 and 2017

Can Barcelona balance domestic demands with the chase for Champions League success? Can Zinedine Zidane plot Real Madrid's path out of the doldrums? And will either of them sign Neymar?

The new La Liga season is one with questions facing all of the leading contenders after a summer of heavy spending - not just Real and Barca, but Atletico Madrid and Sevilla too.

It is a testing start for champions Barcelona, who kick off the campaign away to Athletic Bilbao on Friday.

To preview the season, BBC Sport tackles four key La Liga questions.

Barca refreshed by new duo... and Neymar?

After winning the past two league titles by extremely comfortable margins (11 points last season and 14 points in 2017-18), Barcelona have refreshed their squad with a pair of big-money signings.

Hugely promising Dutchman Frenkie de Jong has arrived from Ajax for 75m euros to energise a midfield where Sergio Busquets and Ivan Rakitic are starting to look their age, while 120m euros secured French World Cup winner Antoine Griezmann from Atletico Madrid to provide much-needed cover and competition for Luis Suarez at centre forward.

However, the biggest deal of all could still lie ahead, with Neymar being lined up for a sensational return from Paris St-Germain - possibly sending Philippe Coutinho in the opposite direction - two years after he quit the Nou Camp in acrimonious circumstances.

It's hard to see how manager Ernesto Valverde could accommodate all his attacking talents if the Brazilian does make the move: a quartet of Neymar, Griezmann, Suarez and captain Lionel Messi in the same starting line-up would be bold beyond belief. So one of them would probably have to sit on the bench, also leaving France international Ousmane Dembele in the cold.

Although president Josep Maria Bartomeu seems set upon securing Neymar as a trophy signing, Barca would arguably be better served by leaving the Brazilian in exile and lining up Griezmann on the left of attack, Suarez through the middle, Messi on the right with the versatile Dembele in rotation.

Regardless of how the squad shapes up by the end of the transfer window, Barca's season will inevitably be played out against the backdrop of their quest to regain European supremacy in the wake of consecutive calamitous second-leg collapses at Roma and Liverpool.

Maintaining focus on domestic duties while also straining for Champions League success will be a tough balance to strike, and the pursuit of Neymar is doubtless intended to ensure the squad is stockpiled with world-class attacking power when the serious stuff rolls around next spring.

That might risk unsettling the squad, but Barca should still be nothing less than leading title contenders once again.

Felix to inspire new-look Atletico?

Joao Felix only appeared in 26 games for Benfica before Atletico Madrid paid 126m euros to sign him

Atletico Madrid, runners-up for the past two seasons, are the most intriguing prospects of the new campaign, with hardy coach Diego Simeone overseeing the biggest squad overhaul of his eight-year reign.

The loss of Griezmann to Barca has been offset by the capture of the third-most expensive player in history, Portuguese starlet Joao Felix; the 126m-euro signing from Benfica concluded a sensational pre-season by scoring a classy winner against Juventus last weekend.

Felix's arrival has sparked suggestions that Simeone will open up into a more expansive style, moving away from his defence-first strategy and allowing his expensive purchase full licence to link up with Diego Costa, Alvaro Morata, Thomas Lemar and Rodrigo Moreno, a new arrival from Valencia.

Realistically, though, Atletico's success this season will largely depend on whether Simeone can instil solidity into a new-look defence following the summer departures of long-serving stars Diego Godin, Filipe Luis and Juanfran.

The reshaped back four contains England international Kieran Trippier, whose challenge to adapt to Simeone's demanding methods will be fascinating to watch over the next few months. Full-backs getting forward to support a narrow midfield has always been a hallmark of Simeone's sides, so the former Tottenham man won't lack opportunities to shine.

Spain international defender Mario Hermoso, young Brazilian left-back Renan Lodi and former Real Madrid midfielder Marcos Llorente are also on the long list of summer arrivals at the Wanda Metropolitano and, if Simeone can get everyone to gel, the reconfigured Colchoneros could become a major force.

Is Zidane under pressure already?

Real Madrid manager Zinedine Zidane is still trying to figure out his strongest side after the club made eight signings this summer

A few miles across the capital, it has also been an eventful summer at Real Madrid, who Zinedine Zidane is attempting to lead out of the doldrums after they fell to 17 defeats in all competitions under three managers last season.

Worrying pre-season performances included a 7-3 thrashing by a Felix-inspired Atletico, and Zidane does not appear to have much idea as to his strongest starting 11 or preferred tactical approach. In the past couple of games, he has even experimented with a 3-5-2 formation - something he has hardly ever employed previously.

This has not been a happy summer for Zidane, frustrated deeply by the failure to lure Paul Pogba away from Manchester United or find a new home for the unwanted Gareth Bale. It is hard to escape the sense that the Real boss is under pressure before a La Liga ball has been kicked.

Despite his silverware-laden first spell in charge, Zidane faces doubts over his tactical nous and wider coaching ability, especially at the head of a team in a transitional period, and those questions will be fully answered in the next few months.

New signing Eden Hazard will play a key role, whether he operates from the left flank or as a support striker to Karim Benzema and/or summer arrival Luka Jovic, and Zidane has the option of further sweeping away his ageing old guard by giving playing time to exciting young wingers Vinicius Junior, Rodrygo Goes, Brahim Diaz and Takefusa Kubo, new defenders Ferland Mendy and Eder Militao and midfielder Fede Valverde.

But the picture is muddied by the potential arrival of Neymar, with club president Florentino Perez eager to challenge Barca in the quest to prise the Brazilian away from PSG.

Quite how Neymar would fit alongside Hazard is anyone's guess, but it would be another engrossing storyline at a club where dull days are rare.

New faces in fourth place?

In the deep south, Seville is probably Spain's most passionate football city: last season saw Sevilla (36,052) and local rivals Real Betis (44,142) attract a combined average attendance of more than 80,000; not bad from a population of fewer than 700,000.

Both clubs have been busy in the summer and head into the season with new managers. Sevilla have given former Spain and Real Madrid boss Julen Lopetegui a (perhaps last) chance to resurrect his faltering career, and the return of legendary sporting director Monchi from an ill-fated stay at Roma has led to a frenzy of transfer activity.

Lopetegui has 11 new signings to call upon, the most important of which could be playmaking midfielder Oliver Torres from Porto. He was a big star at youth level, winning the Under-19 European Championships with Spain in 2012 under the guidance of Lopetegui, and now has the perfect manager with which to blossom.

Across town, Betis also have a new man in charge after poaching Rubi from Espanyol. But it has been a turbulent summer behind the scenes with club legend Lorenzo Serra Ferrer quitting as vice-president following an internal dispute, and the subsequent loss of Giovani lo Celso to Tottenham, Junior Firpo to Barcelona and goalkeeper Pau Lopez to Roma could signify a difficult campaign.

Last season's fourth-placed finishers Valencia have also been troubled by political strife, with popular general manager Mateu Alemany narrowly avoiding the sack after a series of disagreements with Singapore-based owner Peter Lim.

Alemany is a close confidante of manager Marcelino, and any resurfacing of this summer's tensions may undermine the progress made by Los Che in the past couple of years.

The uncertainty at those clubs could open the door for a new face in fourth place, and it will be fascinating to see if unfashionable Getafe can be more than a one-hit wonder after finishing fifth last season. The Azulones have enjoyed a stable off-season, and the retention of highly-rated manager Jose Bordalas could be the most significant 'non-move' of the summer.

Elsewhere, Real Sociedad will be well worth watching after adding Swedish wonderkid Alexander Isak, hard-running winger Portu and Real Madrid youngster Martin Odegaard to complement outstanding forward Mikel Oyarzabal, while fellow Basques Athletic Bilbao will hope striker Inaki Williams can justify a lucrative new contract by leading their challenge for the top four.

Athletic's opening night match-up will help give an early answer to this season's biggest question: Can anyone stop Barcelona?